Control of internal combustion engines



March 23, 1937. E. 1 MULLER CONTROL OF INTERNAL COMBUSTION ENGINES Filed March 18, 1955 Patented Mar. 23, 1937 UNITED STATES PATENT oFFlcE CONTROL OF` INTERNAL JCORIBUSTION ENGINES In Germany 3 Claims.

Many methods have been proposed for controlling internal combustion engines in which fuel is supplied in determined amount by a pump driven by the engine and is admitted to the cyl- 5 inder together with the air required for its cornbustion prior to or during the compression stroke. For example the quantity of air and fuel have been controlled simultaneously by coupled control devices, but that method is not suitable for the engines of vehiclesI for these are required to be highly flexible; engines so controlled would Y induction pipe. lBut this method, too, `does not give satisfactory lresults on vehicles since the adjustment of the fuel pump by the suction is effected through devices which take a certain time to act, while the variation of the quantity of air follows instantly upon change in throttle position. Hence the fuel control lags behind the air control and engines so controlled have poor acceleration. o

In the method forming the subject of this application also the suction in the induction pipe is used to control the fuel supply, but according to the invention, as distinguished from the proposal `above described, the action of the suction extends over only a fraction of the range of control of the fuel pump; on every change `of engine out-y put effected by hand the airvthrottle and the fuel control are adjusted in the same sense through a suitable linkage, and only then does the suction modify the output of the fuel pump should the load conditions so require. l

A further feature of the invention is the coupling of the control means, (herein designated 40 the acceler-ation pedal) with the throttle through a yielding connection so that at the act of regulating for higher load on movement of the control means to increase the engine output,-at any rate when the movement is rapidthe throt- 45 tle movement lags behind the fuel pump control, causing the mixture to be momentarily enriched during acceleration.

Other features of the invention are the employment of the suction to effect automatically a 5o lengthening or shortening of thepump control rod; and a brake or dash-pot which prevents such changes of length occurring quickly.

By way of example a construction according to the invention is illustrated inthe accompany- 55 ing drawing, to show howv the various control de- Apl'll 17, 1935 (Cl. 12S-#139) vices may be arranged and. how they co-operate. The drawing shows such control devices as -might for instance be used for a vehicle engine.

Figure 1 shows the general' assembly f the control devices with the induction pipe of the engine in section.

Figure 2 shows a longitudinal section through the device which lengthens o'r shortens the pump control rod.

The contror devices are shown adjusted for idling; the ,broken lines show their position when the throttle is fullyopen and the pump giving maximum output, a position which they retain on full load on a steep incline, or may take up momentarily during acceleration.

The accelerator pedalCI is connected by a link Y 2 with a three-armed lever 3 turning on azxed pivot; and to this lever are linked the control rod li of the throttle 5 in the induction pipe 6, and the control rod 'l for the fuel pump B. The drawing does notshow the fuel pipes; there can be a common pressure pipe leading to the induction pipe 5' or separate pipes leading to the several branches of the induction pipe or direct to the several cylinders.

On the rod slides a sleeve 9 which is pressed towards a pin II set in the rod Il by a spring I0 located between thesleeve and a disc I2 fastened to the'end of the rod. To the sleeve 9 is pivoted the arm I3 which turns the throttle 5.

If the pedal I isdepressed slowly, spring I0 keeps the sleeve 9 in contact with the pin II, but if quickly the springis compressed transitorily and there results a lag of the movement of the throttle 5, since the parts connected with the throttle tend to retain their position by their inertia. The amount of lag may rbe determined by mechancial, pneumatic or hydraulic brakes. In the construction illustrated the inertia of throttle is'increased by a weighty ring I4 attached to its spindle.

A part of the rod by which the pump output is controlled is constituted by a device I 5 which contracts lengthwise under the suction and which is connected to the suction pipe5 by a flexible pipe II. This device I5 (is shown in section on a larger scale in Figure 2. Its lower part is an elastic I vessel I1 closedl by an endplate 21 into which the `control rod 'I is screwed. At its upper end the vessel I'i is closed by the nearly closed end of a container I6, which is closed at its other end by a cover I9 screwed into it. Below the cover projects a central integral stem2 onv which is formed a. helical web 2l closely iitting the container I8. The elasticvessel Il is lled and the container I8 partly fined-with a non-volame hquid. The nexible pipe I6 is attached to the tubulure 22, and thecontrol arm 2d of the fuel pump is pivotally connected to the eye 23.

The same partial vacuum exists in the device l5 as in the induction pipe 6. The greater the suction the more the elastic vessel I'I contracts under atmospheric pressure; on the suction lessening the elastic vessel tends to resume its original length; so it has a definite length corresponding with any particular pressure in the induction pipe. But its changes of length can occur only slowly, since change of length involves change of interior volume and necessitates liquid being expelled or drawn in through the narrow passage in the interchangeable plug 25 which is screwed into the stem 20,1ts passage opening into a transverse channel through the stem. The long helical channel 26 formed by the web 2| ensures that only liquid and never air has access to the plug 25 notwithstanding vigorous jolting of the vehicle.

To show how the method operates it is useful to consider four typical conditions of load of the vehicle engine, and also those changes from one load to 'another that are of importance in practice.

(l) Low output on the flat: The throttle is only slightly opened, the cylinders receive but a small charge, the engine turns at moderate speed, and the length of the pump controlling rod is such 34) that the pump supplies a quantity of fuel proportionate to the small charge of air.

(2) Full output on the flat: The accelerator pedal I is pressed right down, the lever 3 and throttle arm I3 take the position shown in broken lines, and the throttle is wide open; nevertheless there is a considerable vacuum in the induction pipe because the engine is turning at a high speed. As a result the cylinders do not get a full charge, and the device, I5 is so far contracted that the control arm 24 of the pump cannot reach the position shown in broken lines, and so the fuel supply is restricted to correspond -with the less than full charge of air.

On rapid change from condition (1) to condition (2), i. e. on maximum acceleration of the vehicle withoutuse of vthe change speed gear, the Whole movement of thepedal I is transmitted to thepump control arm, the device I5 being substantially rigid for rapid movements, while the throttle only slowly follows the pedal because of its inertia and the yield of the spring Ill. 'I'hus during acceleration, and only then, a much desired excess of fuel is present.

(3) Low output on an upward incline, and

change from condition (1) to condition (3): TheA throttle may be only opened a little as in condi-u tion (1), but the cylinders get a larger charge because the speed of the vehicle is checked by the incline; the device I5 extends because the suction is less and pushes up the arm 24 so increasing the fuel supply to correspond with the greater charge of air.

(4) Maximum output on an upward incline, and change from condition (2) to condition (4): The pedal is pressed right down, the throttle opened wide; the vehicle speed being checked by the incline the cylinders get a full charge of air, the suction in the induction pipe is small, the device I5 extends, and t'ne pump control arm is put to maximum delivery position, thus again establishing the proper proportion of air and fuel. On changing from condition (3) to ycondition (4) the throttle lags, just as in the change from condition (1) to conditionk (2), and so the mixture is enriched as is desirable for any acceleration.

The essence of the invention is unaiected if two control means are employed for the fuel pump, one operated by hand'with the throttle and the other automatically by the partial vacuum in the induction pipe; it is obvious also that instead of building an elastic vessel into the control rod directly as illustrated, other pneumatic auxiliaries may be employed which in any desired fashion bring about a lengthening or shortening of the pump control rod.

The method of control herein described may be combined with known methods in which the length of the pump control rod is altered not automatically but by hand to correct the proportions of the mixture.

I claim:

1. In an internal combustion engine in which air and fuel are admitted prior to or during the compression stroke, the combination of a fuel pump driven by the engine, means governed by the operator for regulating simultaneously the air and the quantity of fuel delivered by said pump, including a pump control rod, and means for varying the length of said rod automatically in dependance on the suction in the induction pipe to modify the setting of the pump control determined by the operator.

' 2. In an internal combustion engine in which air and fuel are admitted prior to or during the compression stroke, the combination of a fuel pump driven by thc engine, means governed by the operator for regulating simultaneously the air and the quantity of fuel delivered by said pump, including a pump control rod, an elastic vessel included in the length of and formingan effective part of saidrod, and' means connecting the interior of said vessel with the induction pipe of the engine to cause the vessel to contract and elongate under changes of pressure in said pipe.

3. In an internal combustion engine in which l air and fuel are admitted prior to or during the compression stroke, the combination of a fuel pump driven by the engine, means governed by lthe operator for regulating simultaneously the 'air and the quantity of fuel delivered by said pump, including a pump control rod, van elastic vessel included in the length of and forming an effective part of said rod, means connecting the interior of said vessel with the induction pipe lof the engine to cause the vessel to contract and elongate under changes of pressure in said pipe,

and means for delaying such changes of length of said vessel. g

EUGEN LUDWIG MULLER. 

